Abstract: An air-driven dental scaler is provided with a vibrator assembly which comprises a rigid vibrator body having an inner disk-like chamber in which a disk-like rotor is received with a small gap between it and the chamber. The vibrator body is provided with a plurality of inlet ports which are arranged in such a manner that a jet of air impinges upon the cylindrical outer surface of the rotor in a substantially tangential direction to cause the rotor to rotate. As the rotor rotates, it strikes or rolls on the side walls of the chamber to impart a vibratory movement to the vibrator body, which movement is transmitted through a shaft to a scaler tip. The air leaves the chamber through an exhaust port provided, preferably, in one of the side walls of the chamber. The rotor is, preferably, provided with a central opening to enhance the exhaust efficiency.